The invention relates to a radar apparatus for detecting targets, provided with a signal generator with transmitter means coupled to it and receiver means with a video processor coupled to it, antenna means coupled to the transmitter and receiver means, and an indication device suitable for the display, in a first mode with a first range resolution, of a radar picture generated by the video processor, of targets which are in a part of the radar apparatus surroundings.
In a state-of-the-art radar apparatus, the bandwidth of the transmitted signal, the bandwidth of the receiver means and the bandwidth of the video processor and the indication device are usually identical. This bandwidth is determined by a range resolution desired for that radar apparatus.. As known in radar technology, the bandwidth is inversely proportional to the theoretically feasible range resolution. The transmitted signal shall then be provided with some type of modulation which, in conjunction with a matched filter incorporated in the receiver means, realizes the desired range resolution.
If, according to this state of the art, a greater range resolution is to be realized, the transmitter means, receiver means, video processor and indication device shall be adapted accordingly. With the radar apparatus according to the invention, the bandwidth of the video processor and the indication device may be considerably narrower than the above-mentioned, theoretically required bandwidth for realizing a certain range resolution.. This entails that not the entire echo signal of a transmitting signal, but only a portion of this signal selected in time, is used. This may be of advantage when observing a target by means of a radar apparatus and when it is desirable for identification purposes to analyse the target and its immediate surroundings at an increased range resolution.